Power amplifier



FIG. 1 is a perspective in view of the invention;

FIG. 2 is a front view of thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a one side view thereof;

FIG. 5 is an opposite side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

The ornamental design for a power amplifier, substantially as shown and described. 